Author Topic: Improoving Cooling on the 2.1 Sensor /Experimental  (Read 12976 times)

Nikon1

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Re: Improoving Cooling on the 2.1 Sensor /Experimental
« Reply #30 on: February 05, 2021, 05:53:02 AM »
Peltier module coupled to the heat sink  8) ?

 @CS223 and @ anyone who has experience with Peltier Modules (i have none so far), do you have any reccomendations on a temperature-Control-Circut or finished Board/ Unit for Low-Power Peltier Modules? Ideally small size ofc, and if possible some kind of external Display/ Break-Out Potentiometer for Setting The Temperature on the Go.

CS223

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Re: Improoving Cooling on the 2.1 Sensor /Experimental
« Reply #31 on: February 05, 2021, 09:55:01 AM »
Peltier modules are voltage specific from what I recall and need to have decent regulation. So in that regard I would use a PWM circuit, or try anyway, in order to control the cooling level of the module. At least on an experimental basis. On a design basis, I would use a thermostat with feedback similar to how a heated crystal oscillator works so as to keep the imager temperature consistent regardless of the environment. You would want something along the lines of a PID controller as opposed to a slam-bang thermostat. Another option might be a heat pipe on the imager with a Peltier module on the other end if module space is an issue.

Nikon1

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Re: Improoving Cooling on the 2.1 Sensor /Experimental
« Reply #32 on: February 05, 2021, 10:26:54 AM »
Another option might be a heat pipe on the imager with a Peltier module on the other end if module space is an issue.

Was thinking about this also, but since thermal Load Ratings of The heatpipes i looked at, are allways given at 70C, i figured, they are propably not all that Efficient at really low Temps. Bought some and Tested on some ICE Cubes, they do get cold very fast on the other end, when you manage to get decent contact to the Ice, but no real Experience with Low Temp Heatpipe-Stuff, and also couldnt really find any Info anywhere about that...
 If you think it will work well, i am down to Try it maybe.

Nikon1

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Re: Improoving Cooling on the 2.1 Sensor /Experimental
« Reply #33 on: February 05, 2021, 11:30:13 AM »
Peltier modules are voltage specific from what I recall and need to have decent regulation. So in that regard I would use a PWM circuit, or try anyway, in order to control the cooling level of the module. At least on an experimental basis. On a design basis, I would use a thermostat with feedback similar to how a heated crystal oscillator works so as to keep the imager temperature consistent regardless of the environment. You would want something along the lines of a PID controller as opposed to a slam-bang thermostat.

 Thanks for the Infos on the Regulator, and yes, they are Voltage Specific, the one i linked above wants 3,6V and 1.4A to run on full power. Looked a bit into it, and Driving Peltiers seems like a whole rabbithole on its own. However found some old Thread on another Forum about PWM Driving Peltiers, seems to be a bad idea to drive them with PWM, seems to want a Linear Regulated Driver.
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 https://www.mikrocontroller.net/topic/313553
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 [Its in German and about Astro Stuff]
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 I really dont want to build anything which ends up in Programming something, and every else available to Purchase as a ready-to-use-Unit seems to either come in a Huge Form Factor, is very unprecise or surpremely expensive (while those expensive nice ones then lack on-the-Fly adjustment options, and seem to allways need to be connected to a PC to change anything, which also sucks for this Project).
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 https://www.meerstetter.ch/products/tec-controllers
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 I am kind of surprised, that there arent any Controllers for Low power which are easy to use and not huge, but will do some More Research on this and see if i can figure out Some Simple Solution. Otherwise i might end up building some Really basic Linear Driver with some OP-AMPs and a FET or Transistor and a bunch of Potentiometers to be able to adjust everything.
 I assume they should be at least be driven Current Limited or something to not kill them instantly. Guess the "or try anyway" attempt would be worth a Try and just Use some cheap available Thermostat Unit. Not too sure how well it would end up working, because for the #1. Design i wrote about above, there isnt all that much Thermal Mass involved on the Cold side, so it could be end up beeing way to slow, and causing a lot of Temperature Changes all the Time. Pretty sure, it would work fine with most other designs, where there is a Cooler Block of certain Mass involved, this could end up beeing very precise and reliable if tuned in a bit.

Nikon1

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Re: Improoving Cooling on the 2.1 Sensor /Experimental
« Reply #34 on: January 13, 2022, 01:21:27 PM »
Currently thinking about revisiting this with new Cooling Hardware and Firmware to finally figure this out.

Nikon1

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Re: Improoving Cooling on the 2.1 Sensor /Experimental
« Reply #35 on: February 18, 2023, 05:49:33 PM »
Ok, Epic Fail.
 The 2.1 finally running with a Peltier on the Sensor and a Air-Cooler mounted to it, to cool the whole thing.
 However, the added Thermal Load from the Peltier is actually that high, that the Largest Air-Cooler i could Physically fit inside there is not Able to dissipate all that Heat, even with Forced Ventilation from a High Static Pressure Server Fan directly to the Cooler.
 Put a lot of work into this, hoping to get it working without using Heatpipes, but seems i have to come up with an even more Powerful Thermal Solution to finally get to effectively cool the Sensor.
 This just is not working and just produces much more heat overall, causing the Temperatures to run away.
 Stopped Testing when it was raising over 79C, as i finally got an Answer from Krontech saying, that 80C is the Max. Operating Temperature of the Sensor and Processor. When reached, it will Force the internal Fan to 100% Power for 10 Seconds, and if 80C is held for 10 Seconds it will Shut itself off for safety.
 .
 Hoping to post Updates on this soon, but this whole Experimental Cooling Concept now needs a Major Rework to have realistic Chances to actually work after these First Test Results.